package tree;


/**
 * Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

 * For example:
 * Given the below binary tree and sum = 22,
              5
             / \
            4   8
           /   / \
          11  13  4
         /  \      \
        7    2      1
 * return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.
 *
 */
public class PathSum {
	
	public boolean hasPathSum(TreeNode root, int sum) {
        if (root == null) return false;
        if (root.left == null && root.right == null && sum == root.val) return true;
        
        return hasPathSum(root.left, sum - root.val) || hasPathSum(root.right, sum - root.val);
    }

	public static void main(String[] args) {
		// TODO Auto-generated method stub

	}

}
